class_docstr: CelebA-HQ dataset, downsampled as 128x128.
code: def dataset_filename(self):
      return "image_celebahq-128"
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  from tensor2tensor.data_generators import image_utils
  from tensor2tensor.data_generators import problem
  from tensor2tensor.layers import modalities
  from tensor2tensor.utils import metrics
  from tensor2tensor.utils import registry
  import tensorflow.compat.v1
  from tensorflow.compat.v1 import estimator
label_desc: Use image node_id 1 for calling the ImageCelebahq128 obj's underlying member method code with example usage: obj.dataset_filename() and returns: str